| Study | Reason for exclusion |
|---|---|
| ACTION (NCT04332107) | Wrong population: study does not specifically include participants with olfactory dysfunction |
| Begam 2020 | Narrative review article, no primary data |
| Bulbuloglu 2021 | Wrong study design: not a RCT |
| COPPS (NCT04662060) | Wrong population: study does not specifically include participants with olfactory dysfunction |
| Co‐STAR (NCT04422275) | Although this study fits the inclusion criteria for the review, it was withdrawn prior to any participant enrolment |
| COVIDAtoZ (NCT04342728) | Wrong population: study does not specifically include participants with olfactory dysfunction |
| COVIDORL (NCT04361474) | Wrong population: all participants in the study have had symptoms of olfactory disturbance for at least 4 weeks. This study is relevant for the companion review "Interventions for the treatment of persistent post‐COVID‐19 olfactory dysfunction" (O'Byrne 2022). |
| CTRI/2020/08/027477 | Wrong population: study does not specifically include participants with olfactory dysfunction |
| D'Ascanio 2021 | Wrong population: all participants in the study have had symptoms of olfactory disturbance for at least 4 weeks. This study is relevant for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| IRCT20180205038619N2 | Wrong study design: not a RCT |
| IRCT20200522047542N1 | Wrong population: all participants in the study have had symptoms of olfactory disturbance for at least 4 weeks. This study is relevant for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| IRCT20200629047953N1 | Wrong study design: not a RCT |
| IRCT20210708051817N1 | Wrong population: all participants in the study have had symptoms of olfactory disturbance for at least 4 weeks. This study is an ongoing study relevant for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| Islek 2021 | Wrong study design: not a RCT |
| Klug 2021 | The authors have confirmed that not all participants in this trial had COVID‐19 related olfactory dysfunction |
| Le Bon 2021 | Wrong study design: not a RCT |
| NCT04374474 | Although this study fits the inclusion criteria for the review, it was withdrawn prior to any participant enrolment |
| NCT04382547 | Wrong study design: not a RCT |
| NCT04406584 | Wrong population: includes participants with any post‐viral olfactory disturbance (not specifically COVID‐19) |
| NCT04414124 | Wrong population: study does not specifically include participants with olfactory dysfunction |
| NCT04427332 | Wrong study design: observational study, not a RCT |
| NCT04458519 | Wrong population: study does not specifically include participants with olfactory dysfunction |
| NCT04474483 | Wrong population: study does not specifically include participants with olfactory dysfunction |
| NCT04513184 | Wrong population and wrong comparator: study does not specifically include participants with olfactory dysfunction; intervention is compared to intravenous dexamethasone |
| NCT04622891 | Wrong population: study does not specifically include participants with olfactory dysfunction |
| NCT04662086 | Wrong population: study does not specifically include participants with olfactory dysfunction |
| NCT04806880 | Wrong study design: not a RCT |
| NCT04830943 | Wrong study design: not a RCT |
| NCT04853836 | Wrong population: all participants in the study have had symptoms of olfactory disturbance for at least 4 weeks. This ongoing study is relevant for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| NCT04916639 | Wrong patient population: participants in this trial have nasal obstruction and rhinorrhoea, but not necessarily olfactory disturbance. |
| NCT04952389 | Wrong population: all participants will have olfactory dysfunction for ≥ 4 weeks. This ongoing trial will be suitable for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| NCT04964414 | Wrong population: all participants had olfactory loss for at least 60 days. This ongoing trial may be relevant for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| NCT05037110 | Wrong population: all participants in the study have had symptoms of olfactory disturbance for at least 4 weeks. This ongoing study is relevant for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| NL9635 | Wrong population: all participants in the study have had symptoms of olfactory disturbance for at least 4 weeks. This ongoing study is relevant for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| Odorat‐Covid (NCT04598763) | Wrong population: all participants in the study have had symptoms of olfactory disturbance for at least 4 weeks. This study is relevant for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| Patel 2021 | Letter to the editor: no primary data included |
| Pinna 2020 | Letter to the editor: no primary data included |
| Saussez 2021 | Wrong study design: not a RCT |
| SCENT2 (NCT04789499) | Wrong population: all participants in the study have had symptoms of olfactory disturbance for at least 4 weeks. This study is relevant for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| Singh 2021 | Wrong study design: not a RCT |
| Vaira 2021a | Wrong population: all participants in the study have had symptoms of olfactory disturbance for at least 4 weeks. This study is relevant for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| Vaira 2021c | Wrong study design: this is a letter to the Editor, and does not report any primary data |
| Varricchio 2021 | Wrong study design: not a RCT |
| VOLT (NCT04710394) | Wrong population: all participants in the study have had symptoms of olfactory disturbance for at least 4 weeks. This study is relevant for the companion review that considers the treatment of persisting olfactory dysfunction (O'Byrne 2022). |
| Vroegop 2020 | Narrative review article: no primary data |
RCT: randomised controlled trial